The ancient Persian Empire is known for its road systems and postal service, particularly the Royal Road. This extensive network facilitated trade and communication across the vast territories of the empire, which spanned from the Mediterranean to the Indian subcontinent. The Royal Road connected crucial cities, such as Sardis and Susa, enabling more efficient administration and military movement. The Persian postal system, known as the Angarium, featured relay stations and mounted couriers, allowing for rapid transmission of messages across great distances. This infrastructure contributed significantly to the cohesion and control of the diverse regions within the Persian Empire.